The present invention relates to a coolant pump for use with an internal combustion engine. More particularly, the present invention relates to a coolant pump that is mounted directly to the camshaft of the internal combustion engine.
Conventional coolant pumps, also referred to as water pumps, are typically mounted on the front of the engine frame so that the pump can be operated by a belt drive system. Specifically, the output shaft, or crankshaft, of the engine includes a driving pulley fixed thereto forming part of the drive system. The drive system includes an endless belt that is trained about the driving pulley and a sequence of driven pulley assemblies, each of which is fixed to a respective shaft. The shafts are connected to operate various engine or vehicle accessories. For example, one shaft may drive the water pump, and the other shafts may drive such accessories as an electrical alternator, an electromagnetic clutch of a compressor for an air-conditioning system, or an oil pump of the power steering system. With the abundance of accessories, there is limited space in the front of the engine.
To address this issue, it is known to mount the water pump on the back of the engine and operatively connect the pump shaft to the back end of the camshaft in order to drive the pump shaft. An example of this type of water pump is disclosed in U.S. Pat. No. 4,917,052 to Eguchi et al.
However, the camshaft is subjected to torsional vibrations due to, for example, the natural operating frequency of the engine, cyclic resistance to camshaft rotation, and vibrations occurring in the camshaft drive chain/belt. Such torsional vibrations can cause excessive wear in the chain/belt and at the cam surfaces. As a result, it is known to provide vibration damping means for the camshaft so torsional vibrations may be damped. An example of a camshaft damper is disclosed in U.S. Pat. No. 4,848,183 to Ferguson.
Thus, there is a need for a water pump that can be operated by the camshaft of the internal combustion engine and can also act as a torsional vibration damper for the camshaft. Additionally, there is always a need in the automotive art to provide more cost-effective components. The present invention addresses these needs in the art as well as other needs, which will become apparent to those skilled in the art once given this disclosure.
It is an object of the present invention to meet the above-described need.
It is desirable to provide a coolant pump that can be mounted on the engine and operatively coupled to the camshaft to eliminate the use of bearings in the pump.
It is further desirable to provide a coolant pump that has a damper assembly that dampens torsional vibrations of the camshaft.
In accordance with the principles of the present invention, this objective is achieved by providing the combination comprising an internal combustion engine having a crankshaft and a camshaft driven by the crankshaft. The combination further comprises a coolant pump comprising a pump housing fixedly mountable to the engine and including an inlet opening to receive coolant and an outlet opening to discharge coolant. An impeller shaft is mounted directly to the camshaft so as to be concentrically rotatably driven thereby. The impeller shaft extends into the housing in a sealing engagement and in an unsupported relation. A pump impeller is operatively mounted to the impeller shaft within the pump housing. The pump impeller is rotatable to draw the coolant into the pump housing through the inlet opening and discharge the coolant at a higher pressure through the outlet opening.
The objective may also be achieved by providing a coolant pump for use with an internal combustion engine having a crankshaft and a camshaft driven by the crankshaft. The coolant pump comprises a pump housing fixedly mountable to the engine and including an inlet opening to receive coolant and an outlet opening to discharge coolant. An impeller shaft is mounted directly to the camshaft so as to be concentrically rotatably driven thereby. The impeller shaft extends into the housing in a sealing engagement and in an unsupported relation. A pump impeller is operatively mounted to the impeller shaft within the pump housing. The pump impeller is rotatable to draw the coolant into the pump housing through the inlet opening and discharge the coolant at a higher pressure through the outlet opening. It is preferable that this coolant pump be embodied in the combination described above.
The objective may also be achieved by providing the combination comprising a valve controlled piston and cylinder internal combustion engine having a piston driven output shaft and a valve actuating camshaft driven by the output shaft and a coolant system including a coolant flow path which passes through the engine in cylinder cooling relation and thereafter through a cooling zone. The coolant system includes a coolant pump comprising a pump housing within the flow path including an inlet opening configured and positioned to receive coolant from the flow path and an outlet opening configured and positioned to discharge coolant into the flow path. An impeller rotating structure is mounted directly to the camshaft so as to be rotatably driven thereby about an axis concentric to a rotational axis of the camshaft. A pump impeller is operatively mounted to the impeller rotating structure within the pump housing. The pump impeller is constructed and arranged to draw the coolant into the pump housing through the inlet opening and discharge the coolant at a higher pressure through the outlet opening during rotation thereof. A damper assembly is disposed within the pump housing and is rotatable to dampen torsional vibrations of the camshaft.
The objective may also be achieved by providing a coolant pump for use with an internal combustion engine having an output shaft. The coolant pump includes a pump housing including an inlet opening and an outlet opening. An impeller rotating structure is constructed and arranged to be operatively driven by the output shaft of the internal combustion engine about a rotational axis. A pump impeller is operatively mounted to the impeller rotating structure within the pump housing. The pump impeller is constructed and arranged to draw a coolant into the pump housing through the inlet opening and discharge the coolant at a higher pressure through the outlet opening during rotation thereof. A damper assembly is disposed within the pump housing and is constructed and arranged to dampen torsional vibrations of the impeller rotating structure.
In another aspect of the present invention, the pump housing is fixedly mounted to an outer casing of the engine thereby permitting the impeller shaft to be directly coupled to an opposite end of the camshaft to extend into the pump housing in an unsupported relation thereby eliminating the use of bearings in the coolant pump.
Other objects, features, and advantages of this invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, the principles of this invention.